1. Sand to 220 grit
Make sure to sand the surfaces, start with 100 grit and work up to 220 grit to give a clean surface. Use a tack cloth to remove all dust.
2. Clean plywood with mineral spirits
Using a rag, clean everything with mineral spirits. This will highlight any dried glue that needs to be sanded away.
3. Stirred Not Shaken!
Air bubbles are the enemy of staining. They will create a rough finished surface. In order to minimize this, gently stir the conditioner and stain before use, do not shake.
4. Wet your brush
Bubbles can also form within the brush when applying. Always first wet the brush with mineral spirits (when using oil based stains) or water (for water based stains). Wring out brush before dipping in stain.
5. Use a pre-stain conditioner
For soft plywood, use an oil based pre-conditioner (if using oil stain) to help even out the stain application. Many soft plywood will absorb stain differently in different parts of the wood. Adding the pre-stain conditioner helps to temporarily seal the wood to even out this absorption rate. Let sit 10 to 15 minutes before applying stain, but not much longer than that.
6. Choose between a gel stain and an oil or water based stain.
Stain a test piece with your oil or water based stain first to make sure you’re happy with the color!
Gel stains may not need the pre-stain conditioner but it seems the jury is out on that with differing opinions. Use an oil or water based stain (but make sure your pre-stain conditioner is the same, oil or water). Apply according to directions.
Drag the tip of the brush over the stain in long strokes to break any bubbles if they still formed. This is called “tipping off”.
Apply more coats for darker appearance.
7. Sand between applications
Use a fine 220 grit to sand down any raised grain or bubbles that may have formed. Be gentle as the veneer on the plywood is generally very thin.
8. Apply a glossy clear coat
After the last coat of stain has dried completely apply Gloss Polyurethane to seal the surface and give it a glossy finish. Lightly sand between coats, apply at least two coats. If this is for an outside project, select a waterproof finish that is labeled for outdoors.